Dish washing machine spray impeller head



March 20, 1962 A. H. WICKHAM ETAL 3,026,046

DISH WASHING MACHINE SPRAY IMPELLER HEAD Filed May 4, 1959 3Sheets-Sheet 1 22 f A a Q :2 w /7 i i'iiv i' "'W 23 W 1) 2/ 5 I P amFIG. 6.

March 20,1962 w M AL 3,026,046

DISH WASHING MACHINE SPRAY IMPELLER HEAD 3 Sheets-Sheet 2 ddwm Filed May4, 1959 March 20, 1962 H, WICKHAM TAL 3,026,046

DISH WASHING MACHINE SPRAY IMPELLEZR HEAD 3 Sheets-Sheet 5 Filed May 41959 nited States atent @fifice 3,026,046 Patented Mar. 20,1982

3,026,046 DISH WASHING MACHINE SPRAY IMPELLER HEAD Alfred Henry Wickham,Pontyclnn, Glamorgan, Wales,

and Robert John Gilson, New Malden, England, assignors to CharlesColston Limited, London, England,

a corporation of Great Britain Filed May 4, 1959, Ser. No. 810,883

Claims priority, application Great Britain Dec. 23, 1955 4 Claims. (Cl.239-223) This invention relates to liquid impelling apparatus for dishwashing machines comprising a washing chamber having a rotating Waterimpeller arranged to spray washing liquid over soiled dishes etc.,placed in racks in the chamber. This application is acontinuation-in-part of our co-pending US. application Serial No.629,124, filed December 18, 1956, now abandoned.

It is known to use a rotating horizontal impeller in the form of acylinder provided with blades or paddles adapted to scoop or receivewater out of a sump at the bottom of the washing chamber and to throw itin an upward direction to impinge on the soiled dishes, but in such anarrangement it is found that an undesirably large proportion of thedriving motor energy is dissipated in churning or threshing the water inthe sump, and furthermore some of the available kinetic energy in theuseful water discharge from the impeller is dissipated in overcoming theforce of gravity before reaching the soiled dishes. A furtherdisadvantage is the difficulty of separating e.g. by filtration anysolid particles from the soil removed from the dishes, with the resultthat such particles tend to be redeposited on the washed dishes.

t is also known to use a rotatable horizontal spray tube mountedapproximately central of the washing chamber and supplied with waterunder pressure from a separate pump, but in this arrangement it is usualto use the reaction of some of the issuing water spray jets to impartrotation to the spray tube and thus distribute said spray uniformly overthe soiled dishes etc. A disadvantage of this arrangement is that someof the kinetic energy imparted to the water by the pump is dissipated inrotating the spray tube and consequently the washing action iscorrespondingly reduced. It is also found that solid particles of soiltend to be re-deposited on the washed dishes.

It is an object of the present invention to provide a liquid sprayingsystem or apparatus in which undesirable energy losses are avoided sothat the greatest possible proportion of the mechanical energy suppliedby the driving motor is converted into kinetic energy in the jets ofliquid striking the soiled dishes etc.

It is a further object of the invention to provide an improved design ofimpeller capable of discharging jets of liquid all around its sweptperiphery at an angle other than radial and in the direction ofrotation.

The liquid impelling apparatus of this invention is characterised inthat it comprises a revolving spray impeller head having jet orificesfor the discharge of the washing liquid, which jet orifices are at anangle other than radial and face in the direction of rotation of theimpeller or spray impeller head, means being provided within theinterior of the impeller to constrain the mass of liquid therein torevolve bodily with it whereby the effective velocity of the jets willbe equal to the vector sum of the emergent velocity due to impressedcentrifugal head plus-the bodily rotational velocity of the nozzles.

In operation the water delivered by a feed pump emerges from a feed pipeat a rate suflicient to maintain the interior of the impeller full ornearly full. This contained mass of water inside the impeller is forcedto rotate bodily with it by means of non-circular surfaces or axiallyextending ribs on its interior surface and is, therefore, subject tocentrifugal force which causes it to issue from the orifices in the formof jets.

The volume of Water thus discharged by the revolving impeller isdetermined by its peripheral velocity, the total nozzle area and theradial depth of the mass of contained water and in practice these are soadjusted that the rate of discharge from the impeller is equal to therate at which water is supplied by the feed pump.

The impeller is preferably of substantially tubular form and has anaxial length several times greater than its diameter and approximatingto one of the internal dimensions of the washing chamber and mayconveniently have its axis horizontal and parallel to the side walls ofthe washing chamber. The inside of the impeller is provided with axiallyextending ribs, lobes or like non-circular features forming passages forthe liquid, which terminate in jet orifices so spaced as to coversubstantially the whole axial length of the impeller. Alternatively theinternal liquid passages may be so shaped as to form converging nozzlesadapted to discharge liquid jets in the direction of rotation of theimpeller and approximately tangentially to its swept periphery.

The impeller is preferably mounted to rotate on bearings carried by astationary support tube having perforated walls through which liquid issupplied to the inside of the impeller by operation of the feed pump.The impeller may be driven by a spindle passing through the support tubeand having a pulley attached to its outer end, this pulley being drivenby a driving belt which also engages a pulley on the pump spindle.

A heater may be fitted in the sump to heat the washing liquid, andancillary control devices such as valves, timing gear and additivedispensers may be fitted so as to provide a fully automatic cycle ofoperation.

The invention is illustrated in the accompanying drawings in which:

FIGURE 1 is a diagrammatic sectional elevation showing a washing machinefitted with an impeller in accordance with the invention.

FIGURE 2 is a cross sectional view of the impeller or spray impellerhead.

FIGURE 3 is a longitudinal sectional view on the line III-III of FIGURE2.

FIGURE 4 is an end elevation in the direction of the arrow A in FIGURE 5of a further embodiment of the impeller made, for example of pressedsheet steel.

FIGURE 5 is a longitudinal part sectional view of the impeller of FIGURE4.

FIGURE 6 is a diagram showing the arrangement of the drive for the pumpand impeller.

FIGURE 7 is a sectional end elevation showing a modified impeller.

Referring to FIGURES 1 and'2 there is metal cabinet of a washing machinehaving a washing chamber, which is approximately cubical in shapeandincludes side walls I, an end or rear wall 2 and a top wall 3, access tothe interior or washing chamber indicated at 4 being by means of a fullWidth front opening door 5 which is mounted to hinge, preferably asshown, about a horizontal axis 6, so that when open it assumes ahorizontal position thus providing a convenient shelf for supportingcrockery or the like.

A cylindrical impeller or spray impeller head 10, which in theembodiment shown in FIGURES 2 and 3 may consist of a plastic moulding,is mounted to rotate about a horizontal axis being supported at'one endupon hearing 11 carried by a tube 12, the tube 12 in turn being securedby means of a flange 13 at one end thereof to the rear outer wall of thedish washing machine casing.

It will be seen that the tube 12 serves a double purpose since it alsoprovides the means for supply of liquid e.g.

shown the water to the interior of the impeller 10, the water feed beingthrough an inlet opening in the end wall 2 and an elongated slot 15A inthe supply tube (see FIGURE 2). Within the tube wall 12 is a drivingspindle 16, this spindle 16 being journalled to rotate in bearing 17 ina manifold 18, the manifold 18 having offset flanges 20 by which it issecured to the end wall 2 and also providing a passage 21 for the feedwater. Tue drive spindle 16 extends through a bearing '22 in the outerend of tube 12 and has a shouldered end 23 for engagement with anon-circular hole in the outer end of the impeller tube 10, the latterbeing detachably secured thereto by means of a fixing nut 24.

It will be seen that the impeller 10 is mounted within the chamber 4 ina substantially central position so as to provide washing space bothabove and below it for dishes and other articles to be washed.

The bottom wall to the chamber 4 is provided with a sump 25 leading to aport 26, which opens into the lower end of the passage 21. A removablefine mesh wire gauze disc or other screen 27 is provided to act as afilter for the return flow of liquid to the impeller to preventparticles from the dishes being washed passing into the sump and thenceto the pump by means of which water is recirculated to the impeller. Aheater H is located in the sump so as to heat water as desired beforecirculation through the impeller.

A pump indicated at 30 is mounted in the lower portion of the passage21, the pump conveniently being of the centrifugal type but an axial orany other suitable form of pump may be used. The pump 34 is providedwith a spindle 31 which is journalled to rotate in a bearing formed inthe manifold 18. Pulleys 31A and 32, fast on spindles 31 and 16respectively, are driven by a common belt or chain B (see FIGURE 6)which also engages with a pulley P on the driving motor spindle M.

The discharge capacities of the pump 30 and impeller 10 areapproximately balanced so that the impeller is just maintainedcompletely full of water without excess pressure thus avoidingundesirable energy losses in the feed pump.

In operation the water delivered by the feed pump emerges from theperforated wall of the feed tube and builds up inside the hollowimpeller. This contained body of water inside the chamber defined by theimpeller wall is forced to rotate bodily with the impeller by virtue ofthe non-circular internal surfaces or ribs adjacent the impeller wall,and is, therefore, subject to centrifugal force which causes the liquidto be centrifugally forced outwardly against the impeller wall in acompact ringlike mass for being discharged by fluid pressure from theorifices in the form of high pressure jets. The volume of water thusdischarged by the revolving impeller is determined by its peripheralvelocity, the total nozzle area and the radial depth of the body ofcontained water, and in practice these are so adjusted that the rate ofdischarge from the impeller is equal to the rate at which water issupplied by the feed pump.

The total velocity of the jets discharged by the impeller will, ofcourse, be the vector sum of the emergent velocity due to impressedcentrifugal head, plus the bodily rotational velocity of the nozzles. Inpractice, it is found that convenient and eflicient operating conditionsare secured when the dimensions and speed of the impeller are such thatthe peripheral velocity of the impeller at the nozzles is about equal toor greater than the emergent velocity of the jets relative to thenozzles.

In order to avoid undesirable energy losses in the feed pump, it is alsoconvenient to so proportion the discharge capacities of the pump andimpeller that the latter is not completely filled with water, ie theradial depth of water contained within the impeller is less than theradial gap between the nozzles and the outside of the feed tube. Underthese conditions the energy losses in the feed pump are kept to aminimum, and in practice it is found that the power absorbed in drivingthe pump is substantially less than the power absorbed in driving theimpeller. The impeller itself has relatively low energy losses and itfollows, therefore, that the overall efficiency of energy conversion ishigher than obtained in other systems where the whole of the waterenergy is derived from a pump developing sufficient pressure to forcethe washing jets out of stationary of non-energised spray nozzles.

In an alternative construction the impeller may consist of a plaincylinder 40 (see FIGURE 7) in which the discharge orifices are providedby apertures 41 positioned around its periphery, the apertures beingarranged in staggered rows. That portion 42 the impeller adjacent eachaperture 41 and in advance thereof when considered in relation to thedirection of rotation as indicated by the arrow x is bent inwardly sothat the axis of each aperture 41 is in a direction other than radialand does, in fact, approach a tangential position with regard to thecylindrical impeller. Thus spray jets issuing from the interior of theimpeller through the apertures 41 will be in the direction of rotationof the impeller.

An internal rib 43 extending inwardly from the wall of the impeller isprovided adjacent each row of apertures 41 and is located rearwardlythereof in relation to the direction of rotation of the impeller. Theseinternal ribs ensure that the volume of water contained within thecylindrical impeller 49 rotates bodily with the impeller. Dot and dashline 44 indicates approximately :how water inside the impeller willbuild up against one rib.

Referring now to FIGURES 2 and 3 there is shown an impeller cylinder,for example, a plastic moulding, formed with a series of elongated slots33 providing jet orifices arranged in three rows, one row beingindicated at 34 and the other two rows at 34', 34". Each row of orifices34, 34 and 34" is formed in a separate lobe or nozzle head, one of whichis indicated at 35.

In operation liquid is drawn from the sump 25 and delivered to theinside of the supply tube 12 by means of the pump 30 whence it passesthrough the passage 21 to the impeller nozzles 35 and slots 33. Theliquid after discharge from the impeller 10 passes through the filterscreen 27 into the sump 25 before it is recycled by the pump 30.

Referring to FIGURES 4 and 5 a further embodiment of an impeller isillustrated comprising two similar pressed metal sheets assembled toform a cylindrical whole. The impeller is provided with nozzles or lobes37 terminating in discharge slots 36 and, in operation, is mounted onthe supply tube 12 as in the FIGURE 3 construction. 38 indicates a frontplate for attachment to the driving spindle 16, and a back plate 39having bearing 40 mounted therein is also incorporated.

What is claimed is:

1. A liquid impelling apparatus for a dish washing machine, saidapparatus comprising a rotary spray impeller head, a fixed hollowsupport member having perforated walls on which the spray impeller headis mounted for rotation, internal liquid passages in said spray impellerhead, each of said passages having a series of discharge orificesextending lengthwise thereof and the individual orifices facing at anangle other than radial and in the direction of rotation of the sprayimpeller head, means including a pump for supplying liquid to saidsupport member for delivery through said passages and said orifices, andmeans for continuously rotating said spray impeller head oppositely tothe direction of reaction of the jets issuing from said orifices andsaid interior passages causing the mass of liquid therein to revolvebodily with said impeller head whereby the velocity of the jet liquid isthe vector sum of the emergence velocity due to the impressedcentrifugal head of liquid plus the rotational velocity of the jetorifices.

2. A liquid impelling apparatus for a dish washing machine saidapparatus comprising a rotary tubular spray impeller head, a liquidsupply tube on which said spray impeller head is mounted for rotation,means for delivering liquid from said supply tube into said tubularspray impeller head, said spray impeller head comprising a Wall definingan interior chamber and being formed with a series of discharge orificesfacing at an angle other than radial and in the direction of rotation ofsaid spray impeller head, means including a pump for supplying liquid tosaid supply tube for delivery through said orifices, means including adriving spindle extending through said supply tube and being connectedto said spray impeller head for continuously rotating said sprayimpeller head oppositely to the direction of reaction of the jetsissuing from said orifices, and a series of axially extending ribswithin the chamber adjacent said wall to constrain the liquid therein torevolve bodily with said impeller head and thereby to be centrifugallyforced outwardly against said wall in a compact ring-like mass for beingdischarged by fluid pressure outwardly through said jet orifices at saidangle, the velocity of the jet liquid leaving said spray impeller headbeing the vector sum of the emergence velocity due to the impressedcentrifugal head of liquid in the chamber plus the rotational velocityof the jet orifices.

3. A liquid impelling apparatus for a dish washing machine as claimed inclaim 2, in which the means for rotating the spray impeller headincludes a shaft extending through the support member.

4. A liquid impelling apparatus for a dish washing machine as claimed inclaim 2, in which the support member comprises a liquid supply tube andin which the means for rotating the spray impeller head comprises adriving spindle extending through the supply tube and to which spindlethe outer end of the spray impeller head is secured.

References Cited in the file of this patent UNITED STATES PATENTS1,759,629 Riley May 29, 1930 1,997,897 Conley Apr. 16, 1935 2,209,113Dietsche July 23, 1940 2,357,050 McCrum Aug. 29, 1944 2,734,520 AbreschFeb. 14, 1956 2,939,636 Mullin June 7, 1960 FOREIGN PATENTS 209,405Great Britain Mar. 17, 1925

